Introducing skiing to beginners in a naturally hostile environment, the ski slopes, takes its toll both on the student and on ski instruction. That is, before beginners can be taught to ski, they must be taught how to remain upright on their skis. Thus, straight-forward, clear and uncompromised skiing fundamentals generally cannot be taught. On the contrary, to insure that they can instantly assimilate and execute skills introduced just moments earlier, while on their skis, students worldwide are taught a series of progressional techniques or transitional turns that are neither completely succinct nor fundamentally correct. These transitional learning steps are incorporated into the instruction to insure that the common skier can stay on his feet and in control long enough to practice and learn installments of the critical ski skill information.
A number of serious consequences arise from this approach. First, many students cannot discern the insignificant lesson information used as a tool to keep them on their feet from the valuable underlying turning fundamentals to be retained. Second, because of the extent of the transitional emphasis, many ski students ironically walk away from their instruction retaining and basing their technical understanding of skiing on the transitional techniques, e.g. repositioning skis, while forgetting the essential knowledge they were propped up to learn, i.e., the fundamental skills which utilize the turning properties of modern skis to produce the actual turning arcs. A third major consequence is increased time expenditure. To learn and unlearn a variety of transitional techniques significantly prolongs the learning processes. The amount of information presented and the skills to be mastered are quite possibly doubled.
Conventional ski instructional systems do not attempt, nor are they equipped to implement, a new progressional format for ski instruction. More specifically, prior systems are not equipped to institute a significant, and certainly not a total, elimination of transitional techniques, such as beginning novices straight in a parallel stance, to learn uncompromising carving fundamentals. Second, and more importantly, no prior system is equipped to provide the student with an effective interactive environment in which to experience and practice, to a desired degree of competence, a proposed streamlined and uncompromised learning format.
Each manually-controlled physical turn simulation mechanism found in the prior art effectively disqualifies itself from any serious progressional ski instruction role. While a few prior art simulators do allow for the low end conventional transitional movements of skiing (snow plow, christie, etc.), none teaches toward the high end and simulates the goal of every skier: carving.
Carving is the turning action whereby the tail of the ski follows through the same groove cut by its tip to produce an unskidded turning arc. Skidding, the technique taught by conventional systems, is the turning action whereby the tails of the skis do not follow the tips but, rather, washout; that is, the skis are pivoted or forced to slide around the tips in a lateral skidding fashion. To put these two techniques into historical perspective, carving superseded skidding as the racers' choice in the early 60's and a quarter century later is no longer considered a technique exclusive to racing but, rather, is today's standard of effective skiing.
A skier produces a carved turn by setting the ski on varying degrees of edge and pressuring down on the ski to varying degrees. Dependant upon its own particular design and construction, the ski responds by bending into reversed arc corresponding to applied input, ski design and ski-to-snow interaction. With the entire edge passing through the same groove, the ski carves a turning radius determined by the ski's reverse curvature edged into the snow. The critical point is, that although the skier applies the carving input on the ski, it is the ski's own design and turning characteristics that, through edge and deflection, carve the turn radius. Thus, the ski changes its own heading direction.
All known ski simulators, on the other hand, rely on the user to manually change the heading direction of the skis. The user must physically pivot his simulated skis around a horizontal rotational axis, totally eliminating the possibility of simulating the carving action.
For example, the mechanisms disclosed in U.S. Pat. No. 3,807,727 to Ferguson and U.S. Pat. No. 4,396,189 to Jenkins both rely upon the positioning of their horizontal rotational axis ahead of the toe supports. Thus, the tails of the user's skis cannot possibly follow the ski tips path, but are locked unconditionally into swinging laterally around the tips, forcing the user into the unconditional execution of skidding techniques.
Other prior art ski simulators such as disclosed in U.S. Pat. No. 4,629,171 to Krive, utilize a manually rotated platform to simulate turning motion. Although the rotational axis is better positioned than in the case of the Ferguson or Jenkins devices, being placed between the feet, manually operated platforms such as this "condition in" more extreme skidding behavior. To turn or rotate Krive's platform requires user-conscious foot rotation, e.g. "heel-thrust", "rotation", "counter-rotation", all old and well-established skidding techniques. Correct carving technique, i.e. edging and vertical pressuring, will, not generate rotation or turning simulation from such a device.
Plainly, the basis of these prior systems, which is the direct translation of manual pivoting into proportionate rotation, effected on a free-turning mechanism, cannot simulate non-rotational input techniques that utilize the skis' own turning properties to produce the turning output.
First, on the most basic level, if carving input could produce rotation, without some internal/external means of regulating rotational speed, the skis could easily be rotated in a rapid skid-simulating fashion of tails spinning around tips, particularly in an exercise mode of operation. More importantly, without some internal/external means of compensating for the skis actual turning response, or more precisely, without some means of translating the skis' carving-rotational response or output from non- rotational, vertically-applied carving input, there can be no true relationship between carving input and the rotational output.
In contrast, the present invention provides a mechanism that does include physical simulation of the ski's turning action. The invention's physical output mechanism, which physically simulates ski movement, is "modulized" from input devices and controlled by the intervening computational and signal generation functions of a computer system.
In this way, the computer translates non-rotational carving input into accurate turning/carving output by mathematically modeling the event. The computer determines, for similar on-slope conditions, what the user's skis' actual and continuous turning response would be from continuously transmitted inputs. The skis will turn corresponding to the modeled event by constantly updated position command signals generated by the computer and a modulized physical movement mechanism. Beyond true carving simulation, true carving exercise is also provided in this fashion.
Modulization begins with foot-controlled input devices. The input devices in themselves provide no turning-movement simulation. They are strictly input devices, sensing and transmitting to the computer for modeling purposes all the dynamic forces and torques applied to the skis.
An input device not related to skiing, but designed to control video games, is described by Lee in U.S. Pat. No. 4,488,017. Essentially, Lee's controller is a foot-controlled joystick that is straddled by the user. The user positions each foot on either side of the single control unit and, instead of hand manipulation of the joystick, the shifting of the user's weight in the desired direction tilts and aims the joystick element in the desired direction.
Certainly, a skier executing the basis of joystick control and aiming his weight shift in the direction he desires to go will not induce his skis to move him in that direction. No substantial ski-related input information can be generated, sensed and transmitted for ski/carving simulation purposes with Lee's controller. Specifically, although the Lee control unit does tilt to a minimal degree to make electrical contact and produce a directional signal, no effective edging input can be reproduced in this fashion. No inward tilt, no edging with the two inside edges, which are the two essential edges to turn the skis, can be effected by the user and sensed by the controller.
More critically, even though the Lee controller may be pressure activated, it does not differentiate between varying degrees of pressure. It's output signal does not change in proportion to the change in input pressure. Therefore, no evaluation by the computer of those forces which bend the skis into varying curvatures is possible. Weighing and generating varying quantities of weight/force on a ski to bend it into varying reverse curvatures to carve various turn radii is the essence of carving turns. When a skier wants to make sharper turns, he applies more force, sharpening the skis reverse curvature and, thus, sharpening the turn radius.
Furthermore, no evaluation of torque, or of varying degrees of torque is possible with the Lee unit. In contrast, torque is sensed by the input mechanism of the subject invention primarily to detect carving errors. Thus, if the user is twisting one or both feet, this activity cannot be sensed by Lee's device and valuable, possible skid, fall or recovery generating input information is not transmitted to the computer.
In brief, the directional heading of a ski will not turn a ski. It is the forces and torques applied to the ski which turn the ski. Therefore, control units based on positioning a control element in a particular direction and then transmitting a directional signal based on the control elements directional orientation cannot be effective in transmitting pertinent ski input information to a computer; not if carving is to be simulated.
When in contact with the snow, a ski, because of its own external and internal design and flex characteristics, responds to varying forces and torques applied by the user and produces predictable movement on the snow. For the computer to mathematically model and simulate the skis' predictable directional responses, it must process variable measurements of those forces and torques applied to the "skis". Therefore, the input devices must be designed and equipped to continuously present the computer with these variable force and torque measurements.
To alleviate possible confusion, edging in this context is the force application where hip and knee angulation, accompanied with skier's applied weight, provides precise leveraging force to drive the ski edge into the snow to varying degrees and to sustain the particular edge angle driven into the snow.
Referring back to the physical movement mechanism of the present invention, after the computer receives the input values and mathematically determines the skis turning response under similar on-slope conditions, it outputs the response in the form of command signals to the physical movement mechanism. The modeling process can also determine that the skis, beyond carving or skidding various speed and turn radii, because of errant input, will "jet out" from under a skier in some particular fashion. This movement as well would be executed by the physical movement system.
Prior computer controlled vehicular motion simulators, precisely because of their effectiveness in fulfilling their objectives of accurately simulating vehicular motion, are not effective in simulating a skier's motion.
Vehicles, in particular motor vehicles, possess input mechanisms that are completely different from their own output mechanisms. Thus, vehicle simulators provide a separate control loading system, which produces the correct "feel" of input control, and a separate motion system that produces the correct output "motion".
In vehicular terms, a skier's skis, on the other hand, like an ice skater's ice skates, are both the input control device and the movement-producing output device.
What this translates to for a skier, and what a ski simulator must focus on, is that when a skier is skiing, his upper body objective is to stay motionless and all but square to the hill, applying weight and input to skis which, hopefully, are carving left and right arcs, rotating--like a steering wheel--under the upper body's control, and providing the interactive control feedback or "feel" that a steering wheel provides. But, because the skier is standing on the skis, this control feel is also "motion". They are inseparable.
Therefore, a skier is not seated and strapped in a moving compartment to work the input device with ease. Rather, the skier essentially balances on and is strapped to a pair of hybrid input-output devices. With one wrong move, the skier can lose all balance and control. This action is instantly transmitted as out-of-balance, out-of-control input. This causes not only positional and heading havoc, a result of the input function, but the skis charge out from under skier in unrestricted movement which is a result of the skis' output function. This, in turn, causes the user to apply more dramatic inadvertent input to the skis which respond with more dramatic output . This vicious circle has no parallel in the vehicular or vehicular motion simulation world.
Again, in vehicular motion simulators, drivers/pilots are optimally strapped in to apply unhampered input and are optimally buffered from the resulting output to continue applying unhampered input. This interaction is perfectly defined: a control "feel". With skiers, on the other hand, this interaction can lead to a complete loss of control/balance. A skier is not seated within the vehicle being transported; he has simply strapped onto his feet a pair of sophisticated "runners" or skis and must control and face the consequences of losing control/balance while balancing on such elaborate foot attire.
The present invention, with its unique movement axes, attempts to simulates this unique sport. With further reading, the need for the present invention's motion control axes and the lack of utility of prior vehicular control and motion axes will become more apparent.
It is because of ski manufacturing breakthroughs begun during the 1950's that ski technique today is based primarily on the skis' own turning properties to do the turning. The human element is now relegated to standing the most natural way over both skis to edge and flex the control ski into the desired reverse arc. Unfortunately for the student skier, the downside of this natural biomechanical efficiency and ski-oriented technique is that it is visually bankrupt. Novices' eyes cannot discern from those instructors and experts they wish to emulate any relevant visual information beyond a misleading parallel stance. The instructor's technique or body movement will not readily divulge if he is weighing only one ski, the specific ski, where the pressure is being placed (fore, center, or aft), the timing and the degree of edging and weighing, etc. The essence of modern ski technique is all but invisible to the naked eye. This is another major on-slope instruction problem that the simulation instructional system of the present invention attempts to resolve. These internal dynamics must be visually represented in proportion to their importance.
Equally important is the instructor's lack of ability to discern where his students are specifically applying pressure and torque throughout each turn. Students can shift great quantities of weight to the wrong ski, or portion of a ski, without apparent body movement, sending their skis and themselves off into varying degrees of difficulty and leaving their instructor unable to diagnose the problem.
Therefore, those essential, but oftentimes imperceptible, applied forces which the subject invention evaluates toward finding their effect on the skis and the effect of skis to snow, to output and simulate in real time accurate skier motion, can also be evaluated to output and simulate skier's errors, as well as to diagnose and suggest appropriate corrective action to be taken after the errors have been committed.
Simulators such as those disclosed in Laughlin Armstrong's U.S. Pat. No. 4,398,189 and Krive's U.S. Pat. No. 4,629,181, that only sense and transmit information about body position and movement and/or results of body position and movement, cannot detect for diagnostic purposes those specific quantitative forces applied to the skis which send the skiers off into various difficulties. Second, by not placing skis into the equation and, thus, eliminating the most important factor of skiing, not enough information can be attained and transmitted for a computer program to produce an effective numerical representation of the user's carving/skiing output. More specifically, an input device without transmitting those variable forces and torque measurements that a user applies and generates on the skis and the skis generate into the snow through a turn, and do so in a continuous fashion, a real time computational model of the skis and, thus, the users' directional or turning output, cannot be performed. Because no effective direction heading can be mathematically modeled for simulation purposes (again without measuring a vertical force applied to the skis skidding as well as carving is also non-determinable), the system cannot feed back the critical information that a skier uses as the basis for applying an input. The basis of a heading control sport is reading ahead, using environmental feedback to determine how one's inputs and outputs will and do effect attaining a desired heading.
What information the body position sensing systems can and do relay back to the user is his body position performance. In recent ski history, body position was paramount to the recreational skier. Effecting exaggerated body position for stylistic concerns (which hampered actual skiing control and, thus, much opportunity to look stylistic) was to many recreation skiers the major objective. However, in present day skiing, where style is based upon effective and precise heading control, effecting body positions or a series of body positions is a standard instructional rule of what not to do.
Concentrating on body position as an end in itself freezes skiers into posing, into concentrating on their body positions and not coordinating their responses to the environmental circumstances at hand. Prior art ski simulators compound this by urging users, while they are "skiing", to concentrate on and decipher light emitters which signify a different on/off body movement performed by the user. In the day where body movement/position is not a true measure of skier performance, nor a true barometer of what forces will be generated on the skis, and on skis to snow, this approach is both misleading and ineffective. Concentrating on the forces, not on the positions, that the body can generate on the skis or, more precisely, concentrating exclusively on applying those forces on the skis and reading their effect on the slope, is what produces effective heading control skiing. This is what the subject invention attempts to convey and present to the student user.
Film projection display systems, such as described by Armstrong in U.S. Pat. No. 3,408,067 or Diez de Aux, in U.S. Pat. No. 4,074,903 are both completely "open loop". The user's skiing inputs and outputs cause no corresponding change in the predetermined display scenery. Therefore, the user, not being in the loop, cannot see the results of his action. The user cannot use his visual senses to read back from the displayed scenery where his output is taking him and to make judgments on how best to respond with further inputs.
The Health interactive instruction system described by Hon in U.S. Pat. No. 4,490,810, though a closed loop system, is not a closed loop simulator. Correct or incorrect input on a mannequin will trigger either a video disk, computer generated text or audio instruction. However, the student never directly sees or feels the results of his action. The student's input triggers an eventual third person video lesson or second person computer evaluation, but no first person simulation. This is not effective for the instruction and learning of skiing.
Even when a skier standing at rest, has not, but is about to make his first ski-related movement, his movement will be in response to or must take into account his first person on-slope position, heading, lack of motion and position over skis. Once he begins moving, and the faster he moves, and/or the faster he initiates changes in his heading, the more intense must be his concentration in the unbroken flow of feedback information. Now in the loop, all factors begin changing in response to his inputs. Attempting a direction change while moving at speeds of 20-40 miles per hour, with his position changing approximately 30-60 feet per second, what is proper input one moment generally is not the next.
As any beginning student driver can attest, it is a little more than a wild guess as to the correct degree he must turn the steering wheel and apply the brakes to get him in and out of a turn in the desired fashion. Virtually every new student finds he has miscalculated in some fashion (e.g. heading for yellow line/curb), and must correct the wheel, let up or press down on the accelerator. An instant later, he finds he has over-corrected.
However, a skier, unlike a car, does not possess the immediate control of brakes, accelerator and transmission. A skier controls only his direction heading as he "coasts" down a hill. With such lack of control, a skier could be likened to a runaway car and must plan well ahead as to where his direction is taking him. For, indeed, it is only through controlling the direction heading of his skis that a skier can control his speed.
This brings us to another foot controlled bending-beam which produces "carved" turn movement: a skate board. The subject invention also pertains to skateboards. Applied pressure and edge will bend a skateboard and torque the front and/or rear wheels into various turn-angles that, in association, will scribe various "carved" turn radii on the pavement during downhill runs.
In fact, downhill skateboarding is more dependant upon directional control to control speed. On a downhill run, a moments lapse in feedback concentration and application of a directional control will very quickly allow a skateboarder's speed to rise to such a degree that no further direction change is possible--all turns would be too sharp. A skier can at least pivot and skid his skis to a halt, but only hard pavement and a probable crash will await and punctuate a downhill skateboarder's lapse in directional control. In fact, skidding-out in any phase of a turn will cause a downhill skateboarder to crash or bail out.
Therefore, it is the "line", projecting well ahead, and controlling the carved-arc line that is all important to "bending-beam" travel. Though cerebral decision-making may read the environmental feedback to determine the best arc line to take, whether that be deciding where best to free ski a series of arcs or "S" turns, or for racers, determining the best round line through the gates, for any effectiveness, it is almost entirely the unconscious action of the cerebellum that must execute the will. The cerebellum must project forward and apply the precise degree of edge and pressure needed to produce the edged-curvature of the ski that would mirror in degree the curved-line, i.e. the giant radius, it must scribe in the snow to replicate the specific round arced-line of prior decision making. Intellectualizing the precise degree of pressure and edge needed for any one moment, e.g. 120 lbs. at 42 degrees, is not possible. Nor would it be possible to consciously implement these exact force measurements.
In fact, to control a similar but lesser motor act, walking, and consciously direct or think through as much of the motor action as possible, makes for very slow and affected walking, reminiscent of a toddler learning to walk or a stiffly-skiing beginner trying to consciously think his untrained muscles through to each skill execution. It is only through active participation, execution with direct feedback, that the learning process can begin to take shape and then be honed to a level of some involuntary skill before a degree of proficiency can be attained.
No matter how much an instructional system can "show", "tell" and "coach" the skiing student unless the student himself is allowed to see and feel the direct results of his own skiing actions in an accurate closed loop environment (not be told indirectly how he did) to cultivate this interaction, hone these heading control, bending beam skills of a heading control bending beam sport, then there is no reason to apply input and interact with such a system.
The essential ingredient of learning to ski is seeing and feeling the direct results of one's inputs in an accurate environment to cultivate this interaction into effective motor skill execution.
However, this brings us back to square one. Simulating the accurate skiing environment in which to experience the likely feedback that a beginner receives back from the slopes would mean the beginning student could not be taught straight carving fundamentals. On-slope feedback is unmerciful to new skiers.
This is precisely what inspired the conception of the present invention. The entire system is devised around, first, circumventing the unforgiving nature and influence that on-slope skiing has over both the student and his instruction. Second, the thrust of the present invention is aimed at teaching novices in a parallel stance the straight carving fundamentals.
Rather than making the student learn and progress through a variety of transitional ski techniques, the present invention progresses the ski environment through levels of instructional or transitional "realities." This is more conducive to learning in general and specifically allows the student to learn and hone the one objective, i.e. carving technique, in parallel, throughout his education.
The subject method is analogous to the transitional procedure employed by bicycling "students". Beginner and intermediate bicyclists are supplied with transitional bikes. Because of the added lateral support they do supply, transitional bikes "weight" the effect that balance and balance-errors have on the beginner and intermediate riders and, thus, alter the "real world" conditions that a true two-wheeler cyclist experiences. The conditions are altered to keep the student upright and practicing a less exacting motor skill procedure--without altering the skill procedure. This is the objective.
A cyclist can simply get on and ride (pedal and steer) a tricycle, a training-wheel equipped bicycle and then a straight bicycle. He does not have to bow to the elements and become mired in learning and unlearning a variety of different riding techniques to stay up and in control, as does a student skier.
Hence, the primary instructional objective of the system is not to mirror on-slope instruction, but quite the contrary, to take on the transitional burden, as transitional bikes do, and eliminate much instruction practice time and confusion. This is accomplished by altering the simulator's replication of the real world ski environment, again in the same fashion transitional bikes alter their replication of the real world bicycling environment, to allow the student to stay up and practice the most simplistic carving procedure without diverging from carving procedure. The next step is to slowly raise the environmental conditions to real world specifications.
This methodization may include lowering and then raising the input parameters to effectuate objective carving output. This may include lowering and then raising the output conditions, such as controlling the output response to input errors. For instance, if a beginner committed a balance or technical error, the skis natural or real world response of jetting out from under skier would be checked, that is, it would not be physically simulated by the system of the present invention in the initial stages of the instruction. As with tricycles, a grace period is provided for the user to attain a grasp of the skill procedure and not be constantly interrupted with the physical repercussions caused by improper input. Thus, the student would be allowed many uninterrupted repetitions at the positive skill procedure or the working fundamentals.
Once a degree of proficiency has been attained, then the error axes would be triggered to respond. In this fashion, waiting until the objectives are understood and have been physically honed to a sufficient degree, the jetting out of the skis and ensuing loss of balance could be a quick and emphatic reminder of what and what not to do and can become an effective instructional tool. This can be progressed up to and beyond real world specifications. The error axes can be progressed to a state more temperamental then on-slope skiing to demand the utmost skill.
This methodization may include lowering and then raising both the input and output conditions. For example, slow motion lessons can be enacted. Slow motion ski enactment can provide more execution-time between and during skill execution, a more simplified and emulateable sequence and rhythm of skill execution to comprehend and follow. The slow motion lesson would also include an on-screen slow motion instructor to follow. The time scale would then be raised progressively toward real time and real world input and output conditions pulling the student and his motor skill execution up to real world enactment. This methodization may include raising the displayed information beyond real world visuals such as showing the displayed instructor's internal weight/pressure placement throughout the turns for instructional reference.
In combination, these and other forthcoming examples employed by the system of the present invention will pretrain and raise student skiers' parallel carving skills to the point that they would be able to bypass the confusing and time consuming transitional techniques to immediately and safely employ parallel carving technique once they hit the slopes.